Øivind Nilsen

Syphilis epidemiology in Norway, 1992-2008: resurgence among men who have sex with men

BackgroundIn recent years, the number of syphilis cases has stabilised in many countries of Western Europe, however several countries have reported increases among men who have sex with men (MSM). The aim of this article was to describe the epidemiology of early syphilis in Norway in 1992-2008.MethodsCases of early syphilis and congenital syphilis reported to the Norwegian Surveillance System for Communicable Diseases (MSIS) 1992-2008 were described by route of transmission, gender, age, birthplace, stage of disease, HIV co-infection, source partner and place of infection.ResultsThe incidence of reported syphilis ranged from 0.05 (1992) to 1.50 (2002) per 100 000 person-years. Of 562 cases reported to MSIS during the study period, 62% were men infected by another man. The proportion of those, infected homosexually increased from 0 (1992-1994) to 77% (2008). Most of them were Norwegians (83%). The proportion of HIV co-infection among homosexually infected increased over time and reached 39% in 2008. The majority reported being infected by a casual partner (73%) and in the municipality of Oslo (72%). Of 152 heterosexually infected men 64% were Norwegians; 51% were infected by casual contacts and 20% by commercial sex workers; 73% were infected abroad. Among 56 women, 57% were Norwegians, 57% were infected by a steady partner and 40% were infected abroad. Almost half (46%) were diagnosed in the early latent stage. Four cases had congenital syphilis, two of whom were adopted from abroad.ConclusionsSyphilis is rare in Norway, but MSM represent almost two thirds of cases. The increase of HIV co-infected cases among MSM may enhance transmission of both infections. We recommend sexually active MSM to be tested for syphilis 2-4 times a year. Due to its variable clinical course, syphilis might be difficult to recognise at an early stage among women in a low-prevalence population. We estimate current practice of prenatal screening in Norway as sufficient.

Epidemiology of acute and chronic hepatitis B virus infection in Norway, 1992-2009

BackgroundNorway is classified as a low prevalence country for hepatitis B virus infection. Vaccination is only recommended for risk groups (intravenous drug users (IDUs), Men who have Sex with Men (MSM), immigrants and contacts of known carriers). We describe the epidemiology of reported cases of hepatitis B in Norway, during the years 1992-2009 in order to assess the validity of current risk groups and recommend preventive measures.MethodsWe used case based data from the national surveillance system on acute and chronic hepatitis B. The Norwegian Statistics Bureau provided population and migration data and the Norwegian Institute for Alcohol and Drug Research the estimated number of active IDUs between 2002-2007. Incidence rates (IR) and incidence rate ratios (IRR) for acute hepatitis B and notification rates (NR) and notification rate ratios (NRR) for chronic hepatitis B with 95% confidence intervals were calculated.ResultsThe annual IR of acute hepatitis B ranged from 0.7/100,000 (1992) to 10.6/100,000 (1999). Transmission occurred mainly among IDUs (64%) or through sexual contact (24%). The risk of acquiring acute hepatitis B was highest in people aged 20-29 (IRR = 6.6 [3.3-13.3]), and in males (IRR = 2.4 [1.7-3.3]). We observed two peaks of newly reported chronic hepatitis B cases in 2003 and 2009 (NR = 17.6/100,000 and 17.4/100,000, respectively). Chronic hepatitis B was more likely to be diagnosed among immigrants than among Norwegians (NRR = 93 [71.9-120.6]), and among those 20-29 compared to those 50-59 (NRR = 5.2 [3.5-7.9]).ConclusionsIDUs remain the largest risk group for acute hepatitis B. The observed peaks of chronic hepatitis B are related to increased immigration from high endemic countries and screening and vaccination of these groups is important to prevent further spread of infection. Universal screening of pregnant women should be introduced. A universal vaccination strategy should be considered, given the high cost of reaching the target populations. We recommend evaluating the surveillance system for hepatitis B as well as the effectiveness of screening and vaccinating immigrant populations.

Anonymous reporting of HIV infection: An evaluation of the HIV/AIDS surveillance system in Norway 1983–2000

Several European countries are considering implementing surveillance systems for HIV infection, but questions remain regarding patient confidentiality. The population-based HIV/AIDS surveillance system in Norway integrates anonymous HIV case reports from laboratories and clinicians and named AIDS case reports. This evaluation includes a description of the system, evidence of system attributes, estimation of resources for system operations, and documentation of the systems usefulness. HIV case reports provide a far better picture of the epidemic than AIDS reports. The median delay between positive HIV test and reporting was 30 days (interquartile range 18–49 days). Completeness of demographic and epidemiologic information in the surveillance database ranges from 60 to 100%. Information on pre-AIDS mortality and emigration is incomplete. The system cost euro 25,200 in 1999. Results are published every week and used for planning of health care and prevention. We conclude that the Norwegian surveillance system with anonymous reporting of HIV cases is simple, inexpensive and flexible, and capable of providing a representative and timely overview that guides prevention. The system fulfils its objectives while respecting confidentiality and adhering to ethical principles. A similar system may be considered in other countries.

Trends in HIV infection surveillance data among men who have sex with men in Norway, 1995-2011

BackgroundRecent reports on the growing HIV epidemic among men who have sex with men (MSM) in the EU/EEA area were accompanied by an increase of reported HIV among MSM in Oslo, Norway in 2003. Our study with data from 1995 to 2011 has described the recent trends of HIV among MSM in Norway and their socio-demographic and epidemiological characteristics.MethodsThe data were collected from the Norwegian Surveillance System for Communicable Diseases. Cases were described by age, place of infection, clinical presentation of HIV infection, STI co-infection and source partner. We used simple linear regression to estimate trends over time.ResultsDuring the study period, 991 MSM, aged from 16 to 80 years, were newly diagnosed with HIV. No significant trends over time in overall median age (36 years) were observed. Most of the MSM (505, 51%) were infected in Oslo. In the years 1995-2002, 30 to 45 MSM were diagnosed with HIV each year, while in the years 2003-2011 this increased to between 56 and 97 cases. The proportion of MSM, presenting with either AIDS or HIV illness, decreased over time, while asymptomatic and acute HIV illness increased (p for trend=0.034 or less). STI co-infection was reported in 133 (13%) cases. An overall increase of syphilis co-infected cases was observed (p for trend <0.001). A casual partner was a source of infection in 590 cases (60%).ConclusionsThough the increases described could be attributed to earlier testing and diagnosis, no change in the median age of cases was observed. This indicates that it is likely that there has been an increase in HIV infections among MSM in Norway since 2003. The simultaneous increase in STI co-infections indicates risky sexual behaviour and a potential to spread both HIV and other sexually transmitted infections.

No evidence of an epidemic of locally acquired heterosexual HIV infection in Norway.

Background An early sign of a major heterosexual human immunodeficiency virus (HIV) epidemic will be heterosexual infection acquired from persons who were themselves infected through heterosexual intercourse. Goal To test the hypothesis that there is a growing heterosexual epidemic of HIV in Norway. Study Design Data from the mandatory, comprehensive, anonymous HIV case reporting system were analyzed concerning Norwegian residents who had acquired HIV heterosexually and for whom such infections were diagnosed before the year 2001. Results One hundred fifty-five (71%) of 221 men were infected abroad, whereas 107 (76%) of 140 women were infected in Norway (mainly by drug injectors and immigrants); 23 men and 55 women had been infected in Norway by partners who themselves acquired HIV through heterosexual intercourse (secondary heterosexual transmission). There was a slightly increasing incidence of all heterosexual cases and secondary cases. Conclusions Secondary heterosexual HIV transmission remains rare in Norway, and a sustainable epidemic of locally acquired infection seems unlikely in the foreseeable future. The magnitude of the heterosexual epidemic will be strongly influenced by infections acquired abroad.